Net retreat of Antarctic glacier grounding lines

Grounding lines are a key indicator of ice-sheet instability, because changes in their position reflect imbalance with the surrounding ocean and affect the flow of inland ice. Although the grounding lines of several Antarctic glaciers have retreated rapidly due to ocean-driven melting, records are too scarce to assess the scale of the imbalance. Here, we combine satellite altimeter observations of ice-elevation change and measurements of ice geometry to track grounding-line movement around the entire continent, tripling the coverage of previous surveys. Between 2010 and 2016, 22%, 3% and 10% of surveyed grounding lines in West Antarctica, East Antarctica and at the Antarctic Peninsula retreated at rates faster than 25 m yr‾¹ (the typical pace since the Last Glacial Maximum) and the continent has lost 1,463 km² ± 791 km² of grounded-ice area. Although by far the fastest rates of retreat occurred in the Amundsen Sea sector, we show that the Pine Island Glacier grounding line has stabilized, probably as a consequence of abated ocean forcing. On average, Antarctica’s fast-flowing ice streams retreat by 110 metres per metre of ice thinning

Class A GPCR: Di/Oligomerization of Glycoprotein Hormone Receptors

G protein-coupled receptor (GPCR) dimerization and oligomerization was first described over 2 decades ago, contributing to the recent paradigm shift in GPCR signaling of a simplistic, archetypal view involving single receptors activating specific heterotrimeric G proteins at the cell surface, to one of an increasing complex receptor signaling system. However, our understanding of how dimerization and oligomerization, particularly homomerization, generates functional diversity in GPCR signaling is poorly understood. For the Class A/rhodopsin subfamily of glycoprotein hormone receptors (GpHRs), di/oligomerization has been demonstrated to play a significant role in regulating its signal activity at a cellular and physiological level and even pathophysiologically. Here we will describe and discuss the developments in our understanding of GPCR oligomerization, primarily the role of homomeric receptor complexes, in both health and disease, from the study of this unique and complex subfamily of GPCRs